Effects of high pressure on proteolytic enzymes in cheese: relationship with the proteolysis of ewe milk cheese.

Ewe milk cheeses were submitted to 200, 300, 400, and 500 MPa (2P to 5P) at 2 stages of ripening (after 1 and 15 d of manufacturing; P1 and P15). The high-pressure-treated cheeses showed a more important hydrolysis of beta-casein than control and 2P1 cheeses. Degradation of alpha(s1)-casein was more important in 3P1, 4P1, and P15 cheeses than control and 2P1 cheeses. The 5P1 cheeses exhibited the lowest degradation of alpha(s)-caseins, probably as a consequence of the inactivation of residual chymosin. Treatment at 300 MPa applied on the first day of ripening increased the peptidolytic activity, accelerating the secondary proteolysis of cheeses. The 3P1 cheeses had extensive peptide degradation and the highest content of free amino acids. Treatments at 500 MPa, however, decelerated the proteolysis of cheeses due to a reduction of microbial population and inactivation of enzymes.